Plants do not grow but dissolve

I have the following problem: My plants lose all their leaves, or their stems rot. Furthermore, they do not grow any roots. I have added new plants several times, lately even in clay pots. Even fertilizing with sera florena and adding COdoes not help. First I thought it to be because of the gravel and completely emptied my aquarium, so I could add sera floredepot, but also to no avail.

I am about to give up my hobby or purchase plastic plants.

What can I do? Is it maybe caused by bacteria or plant pathogens?

My water parameters:
25 - 27 °C, GH = 5 °dH, KH = 18 °dH, pH = 7, O2 = 5 mg/l, NO2 = 0.3 mg/l

It is very likely that plant pathogens or the like can be excluded, but there are many possible causes:
* High conductivity (above approx. 500 µS/cm). Due to the very high KH (does your tap water really have 5 °dGH und 18 °dKH, or did you use some specific water conditioners?) this actually sounds reasonable to me. Possible salt additions (due to keeping Mollies?) also considerably increases conductivity.

* Possibly high nitrate and phosphate levels (→ lower fish stock, intensify water changes).

* Unsuitable light (→ improve)

* Too dense or sticky bottom gravel.

* Coarse gravel clogged by uneaten food, and is not well suited for plants anyway (it is much more difficult for them to grow roots in coarse gravel than in finer gravel or sand).

NO2 = 0.3 mg/l

If that is really a "=" and not a "≤", something is wrong with the biological filtration! Nitrite must not be detectable when the biofilter is functioning properly. It has hardly any influence on the plants however, but nitrite is toxic for the fish.

Best regards

sera GmbH

Dr. Bodo Schnell


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